A light-emitting heterojunction diode was realized by randomly growth of n-ZnS nanowires, which were synthesized in a home-built vapor transport system, on a p-type SiC substrate. The heterojunction exhibits diode-like rectifying voltage-current behavior with turn-on voltage and reverse bias leakage current equal to ~7 V and = 30 μA respectively. Emission bands with peak wavelengths of ~406, ~478 and ~573 nm are also measured from the room-temperature electroluminescence spectra. These emission bands are related to radiative recombination between electrons from donor levels and holes from either valence band or acceptor level of the ZnS nanowires.